CN113872859A

CN113872859A - IPv6 segmented routing tunnel establishment method

Info

Publication number: CN113872859A
Application number: CN202111206409.5A
Authority: CN
Inventors: 马亨德拉·辛格·尼基; 普雷耶特·卡拉达哈兰; 黄武民
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-07-14
Filing date: 2018-06-20
Publication date: 2021-12-31
Also published as: US20230006924A1; CN110870260A; US20200153732A1; EP3643022A4; JP7412469B2; JP2020526989A; EP3643022B1; KR20210127824A; KR20200019256A; WO2019011114A1; EP3643022A1; JP7174033B2; JP2022069590A; US11962496B2; US11483235B2; EP4191979A1; CN110870260B; KR102315401B1; KR102415794B1

Abstract

The present invention provides a method for establishing a segmented routing tunnel based on the IPv6 data plane through a path computation element communication protocol (PCEP). The method comprises the following steps: a Path Computation Element (PCE) generates a first PCEP message, wherein the first PCEP message comprises indication information and a Segment Identifier (SID), and the indication information indicates that the SID is an IPv6prefix of a node in a tunnel. A first Path Computation Client (PCC) receives a first PCEP message from a PCE and establishes an SRv6 tunnel from the first PCC to a second PCC.

Description

IPv6 segmented routing tunnel establishment method

This application claims priority from the filing of indian patent application with application number IN201741025136, entitled "IPv 6 segment routing tunnel establishment method", filed IN2017, month 7 and 14, the entire contents of which are incorporated herein by reference.

The present application is a divisional application of the chinese patent application having application number 201880045798.8.

Technical Field

The present disclosure relates generally to segment routing, and more particularly to mechanisms for supporting IPv6 forwarding plane segment routing (SRv6) over path computation element communication protocol (PCEP).

Background

Segment Routing (SR) technology utilizes source routing and tunneling modes. It enables any head-end node, i.e. the source node, to select a path in a multi-protocol label switching (MLPS) network independent of a hop-by-hop signaling protocol, such as Label Distribution Protocol (LDP) or resource reservation protocol-traffic engineering (RSVP-TE). Each path is designated as a set of "segments" issued by the link state routing protocol. The segmented routing path may originate from various mechanisms, including IGP Shortest Path Trees (SPTs), explicit configurations, or computed by a Path Computation Element (PCE). These paths may be selected by a suitable network planning tool or may be configured at the ingress node.

For the introduction of the SR architecture, refer to Internet draft-files-rtgwg-segment-routing-00 'segment routing architecture' of Internet Engineering Task Force (IETF) network working group. draft-filsfils-rtgwg-segment-routing-00 defines "IGP segment or IGP SID" as a segment (e.g., IGP prefix or IGP adjacency) attached to a piece of information published by the link state routing protocol. Several types of segments are defined. The IGP node segment represents an IGP-prefix segment that identifies a particular router (e.g., loopback). The term "node segment" or "node SID" is often used as an abbreviation. An IGP adjacency segment, or Adj-SID represents an IGP segment that is appended to a unidirectional adjacency or set of unidirectional adjacencies. The adjacency segment is made available to the node that issued the adjacency segment. Both the node segment and the adjacent segment may be used for SR traffic engineering (SR-TE).

SR can be performed through extensions of intermediate system to intermediate system (IS-IS) and Open Shortest Path First (OSPF) protocols. Segment routing may be coordinated with the MPLS data plane or IPv6 data plane and integrated with a variety of service capabilities of MPLS, including three-layer virtual private network (L3VPN), virtual private line service (VPWS), Virtual Private LAN Service (VPLS), and ethernet VPN (evpn).

The SR architecture may be applied to the MPLS forwarding plane without modification, in which case the SR path corresponds to an MPLS Label Switched Path (LSP). As described in Internet-draft [ I d. ietf-6man-segment-routing-header ], the SR can be applied to the IPv6 forwarding plane using Segment Routing Headers (SRHs).

Reference may also be made to the IETF Internet draft-IETF-isis-segment-routing-extensions, e.g., draft-IETF-isis-segment-routing-extensions-00 "segment routing IS-IS extensions". Further, for the OSPF extension for segment routing, refer to IETF Internet draft-IETF-OSPF-segment-routing-extensions, such as draft-IETF-OSPF-segment-routing-extensions-00 OSPF extension for segment routing.

Reference may also be made to IETF internet draft-IETF-pce-segment-routing-09 "segment routing PCEP extension" (april 2017), which provides more details of segment routing to support segment routing for the MPLS data plane. This document defines a new ERO sub-object, denoted "SR-ERO sub-object", capable of carrying a Segment Identifier (SID) and a node/adjacency identifier (NAI) associated with the SID. SR-capable PCEP speakers (i.e., PCC and PCE) are capable of generating and/or processing such ERO sub-objects.

Thus, draft-ietf-pce-segment-routing-09 specifies an extension of the Path Computation Element Protocol (PCEP) extension portion to support SR-TE 1sp for the MPLS forwarding plane. In this way, a stateful PCE can compute and initiate TE paths, and a PCC can request paths in the SR network that are constrained by certain constraints and optimization criteria.

The IETF Internet draft-IETF-6man-segment-routing-header 06 "IPv 6 Segment Routing Header (SRH) discloses that segment routing can be applied to the IPv6 data plane by adding a new routing extension header.

However, none of these documents defines any mechanism for establishing SRv6 tunnels based on Segment Routing (SR) for IPv6 data plane/forwarding plane.

Therefore, in PCE managed Software Defined Networking (SDN), a mechanism to support segment routing of IPv6 is urgently needed.

Disclosure of Invention

The present invention is provided to introduce concepts related to a method of establishing a segmented routing tunnel that are further described below in the detailed description.

It is an object of the present disclosure to provide PCEP extensions for PCE-managed SDN to establish segmented routing tunnels based on IPv6 data plane. An IPv6 Segment Routing (Segment Routing for IPv6, SRv6) tunnel may be configured in a PCC or initiated by a PCE.

It is another object of the present disclosure to provide a PCC or PCE that indicates its CAPABILITY to support IPv6 SR-Path through a new flag bit in SR-PCE-CAPABILITY TLV during PCEP session initialization.

Accordingly, a first aspect of the present invention provides a method of transmitting data packets in a communication network. The method comprises the following steps: a Path Computation Element (PCE) generates a first PCEP message, wherein the PCEP message includes indication information and a Segment Identifier (SID) field, the SID field includes a plurality of SIDs, and the indication information is used to indicate that each SID in the plurality of SIDs is an IPv6prefix of a node in a tunnel; and the PCE sends the first PCEP message to a first Path Computation Client (PCC) so as to establish an IPv6 segmented routing (IPv6, SRv6) tunnel from the first PCC to a second PCC according to the SID and the indication information.

In one implementation form of the first aspect, before generating the first PCEP message, the method includes the steps of: the PCE receiving a second PCEP message from the first PCC; the PCE sends a third PCEP message to the first PCC, wherein the second PCEP message and the third PCEP message are used to establish an SRv6 capable PCEP session between the first PCC and the PCE, and both the second PCEP message and the third PCEP message carry a SRv6-CAPABILITY Type Length Value (TLV) field, wherein the Type field of the SRv6-CAPABILITY TLV field is used to indicate that both the PCE and the first PCC support SRv6 forwarding.

Accordingly, a second aspect of the present invention provides a method in a communication network. The method comprises the following steps: a first Path Computation Client (PCC) receives a first path computation element communication protocol (PCEP) message from a Path Computation Element (PCE), wherein the PCEP message includes indication information and a Segment Identifier (SID) field, and the SID field includes a plurality of SIDs, and the indication information is used to indicate that each SID in the plurality of SIDs is an IPv6prefix of a node in a tunnel; and the first PCC establishes an IPv6 segment routing (segment routing for IPv6, SRv6) tunnel from the first PCC to the second PCC according to the SID and the indication information.

In one implementation of the second aspect, before receiving the first PCEP message, the method includes the steps of: the first PCC sends a second PCEP message to the PCE; the first PCC receives a third PCEP message from the PCE, wherein the second PCEP message and the third PCEP message are used for establishing a SRv 6-capable PCEP session between the first PCC and the PCE, both the second PCEP message and the third PCEP message carry a SRv6-CAPABILITY TYPE Length Value (TLV) field, and wherein the Type field of the SRv6-CAPABILITY TLV field is used for indicating that both the PCE and the first PCC support SRv6 forwarding.

Importantly, the SID field and the indication information may be carried by an Explicit Route Object (ERO) sub-Object that supports SR IPv6 variable length SIDs. The ERO sub-object in this application may also be referred to as the SRv6-ERO sub-object. The indication information may be bits, i.e., SRv 6-I bits of the ERO sub-object, modified to support SR IPv6 variable length SIDs. Which indicates that the SID is of variable length (i.e., 16 bytes encoding the IPv6 prefix), as opposed to 4 bytes in the old sub-object. The ERO sub-object may be carried in at least one or more of a PCUpd message, a pcinitial message, and a PCRep message to convey an explicit path from the PCE to the PCC.

Optionally, the first PCEP message (which may be a pcinitial message or a PCRep message) further includes a PATH-SETUP-TLV field, wherein the type field of the PATH-SETUP-TLV field indicates that the tunnel is established by the SRv6 technique. The second PCEP message (which may be a PCReq message) further includes an SRv6-CAPABILITY Type Length Value (TLV) field, wherein the Type field of the SRv6-CAPABILITY TLV field indicates that the first PCC supports SRv6 forwarding. The third PCEP message (which may be a PCRep message) further includes an SRv6-CAPABILITY Type Length Value (TLV) field, wherein the Type field of the SRv6-CAPABILITY TLV field indicates that the PCE supports SRv6 forwarding.

Optionally, the PCC is configured to send a Path Computation Report (PCRpt) message for updating a Link-State-Database (LSDB) to the PCE. The PCE determines the IPv6 LSDB through a Path Computation Element Protocol Link State (PCEPLS), a Border Gateway Protocol Link State (BGPLS), an Interior Gateway Protocol (IGP), or any combination thereof. The PCE is configured to modify the path and send an update message (PCUpd) message to the PCC.

First, the PCC and the PCE may each exchange SRv6 capability TLVs via Open messages for establishing SRv6 capabilities during the PCEP session. For example, the PCC may first send an Open message to the PCE indicating that the PCC is able to establish SRv6 a session. In response, the PCE sends an Open message to the PCC indicating that the PCE is also capable of establishing SRv6 sessions. And transmitting the actual path from the PCC to the PCE by a Route Record Object (RRO) carried in the PCRpt message and/or the PCReq message sent by the PCC.

Therefore, in the prior art, the forwarding node can calculate the SRv6 tunnel path, but is limited to the region, and cannot establish an optimal inter-region/inter-AS tunnel. In various embodiments of the present invention, the PCE may optimally establish intra-area, inter-area, and inter-AS SRv6 tunnels. Thus, the IPv6 data plane may enable the establishment of a segmented routing tunnel with a PCE even if the forwarding network does not support MPLS.

The various options and preferred embodiments mentioned above in relation to the first implementation are also applicable to the other implementations in relation.

Drawings

The description is made with reference to the accompanying drawings. In the drawings, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. The same numbers are used in the drawings to reference like features and components.

Fig. 1 shows a process flow of a method for establishing a segment routing tunnel based on an IPv6 data plane (SRv6) initiated at a PCC or by a PCE according to a first embodiment of the present invention.

Fig. 2 shows a flowchart of SRv6 tunnel configuration at PCC provided by the first embodiment of the present invention.

Fig. 3 illustrates a flow diagram of a PCE-initiated SRv6 tunnel provided by a second embodiment of the present invention.

Fig. 4 illustrates a schematic diagram of an SRv6 tunnel established by a PCE provided by an embodiment of the present subject matter.

Fig. 5 is a schematic diagram illustrating SRv6 packet forwarding according to an embodiment of the present subject matter.

Fig. 6 illustrates the format of an SRv6 capability TLV provided by an embodiment of the present subject matter.

Fig. 7 illustrates a path setup Type TLV (add PST Type 2) provided by an embodiment of the present subject matter.

Fig. 8 illustrates SRv6 an Explicit Route Object (ERO) sub-Object provided by an embodiment of the subject matter.

Fig. 9 illustrates SRv6 Route Record Object (RRO) sub-objects provided by an embodiment of the subject matter.

Fig. 10 illustrates a schematic diagram of a PCE provided by an embodiment of the present subject matter.

Fig. 11 illustrates a schematic diagram of a PCE provided by an embodiment of the present subject matter.

Fig. 12 illustrates a schematic diagram of a PCC provided by an embodiment of the present subject matter.

Fig. 13 shows a schematic diagram of a PCC provided by an embodiment of the present subject matter.

It is to be understood that the attached drawings are for purposes of illustrating the concepts of the application and may not be drawn to scale.

Detailed Description

The application can be implemented in numerous ways, including as a process, an apparatus, a system, a composition of matter, and a computer readable medium such as a computer readable storage medium or a computer network wherein program instructions are sent over optical or electronic communication links. In this specification, these implementations, or any other form that the application may take, may be referred to as techniques. In general, the order of the steps of disclosed processes may be altered within the scope of the application.

The following provides a detailed description of one or more embodiments of the application and accompanying drawings that illustrate the principles of the application. The present application is described in conjunction with these embodiments, but the present application is not limited to any embodiment. The scope of the present application is limited only by the claims and the present application includes many alternatives, modifications, and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the present application. These details are provided for the purpose of example and the application may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the application has not been described in detail so that the application is not unnecessarily obscured.

Numerous specific details are set forth in the following description in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application may be practiced without these specific details. In other instances, well-known methods, procedures, components, modules, units and/or circuits have not been described in detail so as not to obscure the present application.

Although embodiments of the application are not limited in this respect, discussions utilizing terms such as processing, computing, calculating, determining, establishing, analyzing, checking, or the like, may refer to operation(s) and/or process (es) of a computer, a computing platform, a computing system, or other electronic computing device, that manipulate and/or transform data represented as physical (e.g., electronic) quantities within the computer's registers and/or memories into other data similarly represented as physical quantities within the computer's registers and/or memories or other information non-transitory storage medium that may store instructions to perform operations and/or processes.

Although the embodiments of the present application are not limited thereto, the terms "plurality" and "a plurality" as used herein may include, for example, "a plurality" or "two or more". The term "plurality" may be used throughout the specification to describe two or more components, devices, elements, units, parameters and the like. Unless explicitly stated, the method embodiments described herein are not limited by a particular order or sequence. Additionally, some of the described method embodiments or elements thereof may occur or be performed concurrently.

The embodiment of the invention teaches a method for establishing a segmented routing tunnel based on an IPv6 data plane through Path Computation Element Protocol (PCEP) extension. A Path Computation Element Protocol (PCEP) runs on a Path Computation Client (PCC) and a Path Computation Element (PCE) to establish communication between the PCC and the PCE. A PCE is capable of computing network paths or routes based on a network graph and applying computational constraints.

Although aspects of the method of establishing a segment-routed tunnel based on the IPv6 data plane by extending PCEP are described, the present application may be implemented in any number of different computing systems, environments, and/or configurations, which are described in the context of the following exemplary systems, devices/nodes/apparatuses and methods.

In the following, embodiments of the disclosure are explained with the help of exemplary diagrams and one or more examples. However, such exemplary diagrams and examples are provided for illustrative purposes to better understand the present disclosure and should not be construed as limiting the scope of the present disclosure.

The method is applied to a system comprising a PCC and a PCE, wherein the PCC and the PCE run PCEP and communicate with each other.

Ietf internet draft document (RFC5440) "Path Computation Element (PCE) Communication Protocol (PCEP)" describes PCEP for Communication between a PCC and a PCE or between a pair of PCEs. In the present invention, the basic PCEP operations in the SR network follow the Internet draft document draft-ietf-pce-segment routing. The SR-IPv6 LSP computed by the PCE may be represented in one of the following forms:

an ordered set of IPv6 prefixes representing network nodes/links.

An ordered set of IPv6 SIDs.

An ordered set of both IPv6 prefixes and IPv6 SIDs.

The present invention extends the "SR-ERO sub-object" as defined in I-D.ietf-pce-segment-routing to carry IPv 6SID (IPv6 address). A PCEP speaker with SRH capabilities should be able to generate and/or process such ERO sub-objects. The ERO containing the SR-ERO sub-object may include a PCEP path computation response (PCRep) message defined in [ RFC5440], a PCEP LSP initiation request message (pcinite) defined in the Internet draft document I-d.ietf-pc-initiated-LSP, and PCEP LSP update request (pcadd) and PCEP LSP status report (PCRpt) messages defined in the stateful PCE [ I-d.ietf-pc-stateful-pc ].

The extensions specified in the present invention supplement the existing PCEP specification to support SRH paths. Thus, PCEP messages (e.g., path computation requests, path computation responses, path computation reports, path computation updates, path computation initiations) must be formatted according to ietf Internet draft documents (RFC5440), Internet draft I-d.ietf-pc-stateful-pce, Internet draft I-d.ietf-pc-initiated-lsp, and any other applicable PCEP specification.

The present invention uses the following terms:

PCC: a path computation client requesting any client application program for performing path computation by the path computation unit.

PCE: a path calculation unit; an entity (component, application, or network node) that is capable of computing network paths or routes and applying computational constraints based on a network graph.

PCEP: and a path computation unit protocol.

SR: and (4) segmented routing.

SID: a segment identifier.

SRv 6: IPv6 forwards planar segment routes. SRv6 may also be referred to as SR-IPv 6.

SRH: IPv6 segment routing header.

SRH path: segment IPv6 (IPv6 SR domain IPv 6SID list representing path)

A Path Computation Client (PCC) and a PCE provided by embodiments of the present invention include a processor, a memory, and an interconnection mechanism respectively coupling the memory and the transceiver. A processor may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitry, and/or any devices that operate on signals based on operational instructions. Among other capabilities, at least one processor is configured to retrieve and execute computer-readable instructions stored in the memory to implement the methods of the present invention.

The memory may include any computer-readable medium known in the art, including, for example, volatile memory (e.g., Static Random Access Memory (SRAM) and Dynamic Random Access Memory (DRAM)), and/or non-volatile memory (e.g., Read Only Memory (ROM), erasable programmable ROM, flash memory, a hard disk, an optical disk, and a magnetic tape).

The Path Computation Element (PCE) and the PCC include a transceiving Element and a processing Element. The transceiving unit is used for executing receiving and sending actions in the method, and the processing unit is used for executing other actions except transceiving actions in the method. For example, a processing unit of the PCE is configured to generate a first path computation element communication protocol (PCEP) message, where the first PCEP message includes indication information and a Segment Identifier (SID) field; the SID field comprises a plurality of SIDs, and the indication information is used for indicating that each SID in the plurality of SIDs is respectively an IPv6prefix of a node in a tunnel; the PCE transceiving unit is configured to send the first PCEP message to a first Path Computation Client (PCC) to establish a segment routing (IPv6 for IPv6, SRv6) tunnel from the first PCC to a second PCC according to the SID and the indication information. For another example, a transceiving unit of the PCC is configured to receive a first path computation element communication protocol (PCEP) message from a Path Computation Element (PCE), where the first PCEP message includes indication information and a Segment Identifier (SID) field, the SID field includes a plurality of SIDs, and the indication information is used to indicate that each SID of the plurality of SIDs is an IPv6prefix of a node in a tunnel; and the processing unit of the PCC is configured to establish an IPv6 segment routing (segment routing for IPv6, SRv6) tunnel from the first PCC to the second PCC according to the SID and the indication information.

While the present subject matter is explained in the context of the present invention being implemented as a PCC or PCE, it is to be appreciated that the PCC or PCE may also be implemented in various computing systems, such as a laptop, desktop, notebook, workstation, mainframe computer, server, network server, or the like. It should be understood that a PCC or PCE may be accessed by multiple users through one or more user devices (not shown) (collectively referred to above/hereinafter as users) or through an application resident on a user device. Examples of a PCC or PCE may include, but are not limited to, a router, a switch, a controller in an SDN, a portable computer, a personal digital assistant, a handheld device, and a workstation. The PCC and PCE are communicatively coupled by a network.

The invention extends PCEP to support SRv6 tunnels to support IPv6 capabilities (in Open object/Open messages), IPv6 prefixes SR-Stack (in SR-ERO sub-objects) and new path establishment types (in RP/SRP objects). With these extensions, the PCC may create a tunnel, or the PCE may send a request to the PCC to create a tunnel based on SRv6 (e.g., to create an IPv6 tunnel based on SRH techniques defined in IETF draft-IETF-6 man-segment-routing-header-06).

In SR networks, the ingress node of the SR path appends an SR header (SRH) to all outgoing messages, the SR header consisting of a list of SIDs (i.e. IPv6 prefixes in the case of SRH-IPv 6). The header has all the necessary information to direct the message from the ingress node to the egress node of the path, and therefore does not require any signaling protocol. The present invention describes the extension of the SR path of the IPv6 forwarding plane. The SR path (i.e., ERO object) consists of an ordered set of SIDs. The PCC or PCE indicates its CAPABILITY to support IPv6 SR-path during PCEP session initialization through a new flag in SR-PCE-CAPABILITY TLV format.

Fig. 1 illustrates a process flow of a method for establishing a segment routing tunnel on an IPv6 data plane (SRv6) configured at a PCC or initiated by a PCE according to an embodiment of the present invention. In one method, when the PCC configures the tunnel, a second PCEP message is received from the PCC before the PCE sends the first PCEP message, where the second PCEP message may be a pcereq message. The PCE sends a third PCEP message to the PCC. The third PCEP message is a PCRep message.

In this embodiment, the method 100 includes the following steps for sending a data packet in a communication network through an SRv6 tunnel:

step 102, a Path Computation Element (PCE) generates a first PCEP message, where the PCEP message includes indication information and a Segment Identifier (SID) field, the SID field includes a plurality of SIDs, and the indication information is used to indicate that each SID of the plurality of SIDs is an IPv6prefix of a node in a tunnel. Optionally, the ERO object may be included in the first PCEP message to carry the indication information and the SID field. The indication information may be one bit, but the present invention is not limited thereto.

Step 103, the PCE sends the first PCEP message to the first PCC to establish an SRv6 tunnel from the first PCC to the second PCC according to the SID and the indication information.

Step 104, a first Path Computation Client (PCC) receives a first path computation element communication protocol (PCEP) message from a Path Computation Element (PCE), where the first PCEP message includes indication information and a Segment Identifier (SID) field, the SID field includes multiple SIDs, and the indication information is used to indicate that each SID of the multiple SIDs is an IPv6prefix of a node in a tunnel.

Step 105, the first PCC establishes an IPv6 segment routing forwarding plane (SR-IPv6) tunnel from the first PCC to the second PCC according to the SID and the indication information.

In various embodiments of the invention, the first PCEP message may be selected from a Path Computation initiation (pcinite) message, the second PCEP message may be selected from a Path Computation Request (PCReq) message, and the third PCEP message may be selected from a Path Computation Reply (PCRep) message. The PCEP message may also be selected from an update message (PCUpd) or a LSP status report (PCRpt).

Fig. 2 illustrates a flow diagram of a method 200 for configuring an SRv6 tunnel initiated by a PCC. It shows the following steps:

step 300, establishing SRv6 capable PCEP session by exchanging SRv6 PCE capability TLVs in open messages;

step 301, the PCC configures a Path-setup-type SRv6 (i.e., PST ═ 2) tunnel;

step 302, the PCC sends a path computation request (PCReq) message to the PCE;

step 303, after computing a path based on SRv6 path-setup-type (i.e. PST ═ 2), PCE sends a path computation response (PCRep) message to PCC;

step 304, the PCC sends a path computation report (PCRpt) message to the PCE to host the tunnel, the state of the tunnel originating from connectivity detection of the BFD or OAM mechanism;

step 305, the PCE modifies the path and sends a path computation update (PCUpd) message to the PCC.

Fig. 3 illustrates a flow chart of a method 300 for configuring a PCE-initiated configuration SRv6 tunnel provided by a second embodiment of the present invention, which shows the following steps:

step 400, establishing SRv6 capable PCEP session by exchanging SRv6 PCE capability TLVs in open messages;

step 401, the PCE configures a path-setup-type SRv6 (i.e., PST ═ 2) tunnel and computes a path based on SRv6 path-setup-type (i.e., PST ═ 2);

step 402, PCE sends a path initialization tunnel request (PCInitiate) message to PCC;

step 403, the PCC sends a path computation report (PCRpt) message to the PCE to host the tunnel, the state of the tunnel originating from connectivity detection of the BFD or OAM mechanism;

step 404, the PCE modifies the path and sends a path computation update (PCUpd) message to the PCC.

Fig. 4 shows a schematic diagram of an SRv6 tunnel established by a PCE. The PCE sends a first PCEP message to a first PCC node (ingress node). The message contains ERO according to the format as shown in fig. 8.

Fig. 5 is a schematic diagram illustrating SRv6 packet forwarding based on the SRv6 data plane according to an embodiment of the present subject matter. As shown in the figure, at ingress, the PCC downloads SRv6 IPv6prefix SIDS as SRv6 next header list. The Destination Address (DA) is updated at each transmitting node. The PCE updates the ingress node through SRv6 ERO. When the message is received at the ingress, it applies SRv6 ERO as the next header of SRv6 and forwards the message to A, DA [1A1] (i.e., from the bottom of the next header). At A, the DA is updated to [ A2B1], and the message is forwarded to B. At B, DA is updated to [ B2C1], and the message is forwarded to C; at C, the DA is updated to [ C2D1], and the message is forwarded to E (i.e., the final destination).

In this embodiment, an SRv6 capable PCEP session is established between the PCC and PCE via an OPEN message before generating the first PCEP message. The SRv6-PCE-CAPABILITY TLV was introduced in the present invention, but is an optional TLV associated with the OPEN Object to exchange the SR IPv6 CAPABILITY of the PCEP speaker. The PCE and PCC exchange open messages to establish an SRv6 capable PCEP session. The PCC or PCE must encode the SRv6-PCE-CAPABILITY TLV in the open message. When a PCEP session is established between the PCC and PCE, the two PCEP speakers exchange their capabilities to indicate their capabilities to support SRH-specific functions.

Fig. 6 illustrates an updated format of the SRv6 capability TLV provided by an embodiment of the present subject matter. This TLV is for an iPv6 data plane based SR, not for an existing TE for SR-TE. The format of the SRv6-PCE-CAPABILITY TLV is shown. The encoding point for the TLV type is TBD as defined by IANA. The TLV is 4 octets long and is of variable length. The 32-bit value is formatted as follows: MAX-SL is "maximum SID depth", and the (1 octet) field (MSD) specifies the maximum number of SIDs, PCC can be applied as an MPLS label. The "SRH MSD" (2 octets) field (SRH MSD) specifies the maximum number of SIDs that the PCC can add as the next header in SRH. The length of the flag field is 1 octet, and the invention defines the following marks:

l mark: the PCC sets this flag to 1 to indicate no restriction on MSD.

The exchange of SR capabilities is the same as described in the Internet draft-ietf-pce-segment-routing of the prior art. Accordingly, in the interest of brevity, no further description is provided herein.

In this embodiment, the PCE is aware of IPv6 LSDB via the PCEPLS/BGPLS/IGP protocol. The IPv6prefix sid is issued by IGP for each IPv6 adjacency. The PCC and PCE must be BGPLS/IGP or PCEPLS capable, and the PCC can update Link-State-database (LSDB) to PCE. The PCE updates the network topology from the received LSDB and computes a path using the LSDB.

In the described embodiment, PCE encodes SRv6_ ERO in PCRep (i.e., if a PCReq message is sent from a PCC to the PCE), PCUpd (i.e., if an LSP is delegated from a PCC to a PCE), pcinitial (i.e., if a tunnel is initiated by a PCE). The PCC encodes SRv6_ RRO in the PCRpt (i.e., in the path computation report sent from the PCC to the PCE).

In one embodiment of the present invention, to establish a tunnel using IPv6, the PCE uses SRH techniques to support SRv 6-based tunnel establishment. The PCC configures a tunnel using a path-setup-type SRv6 (i.e., PST ═ 2). PATH-SETUP-TYPE is defined in PATH-SETUP-TYPE TLV (2). Fig. 7 shows the format of the path setup type TLV (add PST type 2). This TLV is encoded in an RP/SRP object, which may be encoded in PCUpd (for identifying transactions from the PCE) and PCRpt (i.e., for matching transactions received from the PCE) messages, as specified in the Internet draft document draft-ietf-PCE-lsp-setup-type.

Fig. 8 and 9 illustrate SRv6 an Explicit Route Object (ERO) sub-object and SRv6 a Route Record Object (RRO) sub-object, respectively, provided by an embodiment of the present invention, wherein a SID is a segment identifier and a node or adjacency identifier (NAI) contains the NAI associated with the SID.

In this embodiment, the SR-ERO/SR-RRO sub-object is modified to support the variable length SID of SR IPv 6. Indication information, i.e. bit (I), is introduced indicating that the SID is of variable length (i.e. 16 bytes for encoding IPv6 Prefix), unlike the 4 bytes in the old sub-object. The ERO object is encoded in a PCUpd, pcinite, or PCRep message to convey an explicit path from the PCE to the PCC. The RRO object is encoded in the PCRpt message to transfer the actual path from the PCC to the PCE, or the RRO object may be encoded in the PCReq message.

In one embodiment, to support IPv 6SIDs, the indication information, i.e., the new bit (I), is set in the existing SR-ERO sub-object. If the I bit is set, the SR-ERO sub-object consists of a 32-bit header followed by an IPv 6SID and a NAI associated with the IPv6 SID. If the I-bit is set, the length field is variable, unlike that defined in the Internet draft document I-D. The SR-ERO sub-object format is shown in FIG. 9. The fields in the SR-ERO sub-object are as follows:

the "L" flag is defined as in Internet draft document I-D.

Type as defined in Internetdraft-ietf-pce-segment-routing.

Length contains the total length of the child object in octets, including L, type and length fields. The length must be a multiple of 4. As previously mentioned, the SR-ERO sub-object must have at least a SID or a NAI. The length takes into account the SID or NAI only if it is not empty. Flags are described below to indicate whether the SID or NAI fields are empty.

The SID Type (ST) indicates the type of information associated with the SID contained in the object body. ST values are defined in draft-ietf-pce-segment-routing. For the SRH path, the effective ST values are 2 and 4.

The flag is used to carry any additional information about the SID. In the embodiment of the present invention, a new bit (I) is defined.

M: when this bit is set, the SID value represents the MPLS label stack entry as specified in [ RFC5462], where only the label value is specified by the PCE.

I: when this bit is set, the SID value represents the IPv6 SRH stack entry as specified in [ I-D.ietf-6man-segment-routing-header ]. If the M bit is set, the I bit cannot be set, and vice versa, otherwise the PCEP speaker must send a PCErr message with an error type of 10 ("receive invalid object") and an error value of TBD ("Bad SID format").

The other positions are as defined in draft-ietf-pce-segment-routing.

In this embodiment, the ERO process remains unchanged except for the process of defining a new flag bit (I) and a variable SID (i.e., prefix SID), and if the PCEP speaker does not support prefix SID, it must send a PCErr message with an error type of 4 (unsupported object) and an error value of 2 (unsupported object type). If the M bit is set, the I bit cannot be set, and vice versa, otherwise the PCEP speaker must send a PCErr message with an error type of 10 ("receive invalid object") and an error value of TBD ("Bad SID format").

To support SRH, only the SR-ERO sub-object is modified, and other RRO related sub-objects and processes must follow the specifications as in Internet draft I-D. The SRIPv6-ERO sub-object consists of a 32-bit header followed by a variable (SID) Prefix SID and an NAI associated with the Prefix SID.

In this embodiment, a PCEP speaker that does not support SR PCEP capability cannot recognize SR-ERO or SR-RRO sub-objects with a new (I) flag, and must transmit PCEP errors with an error type of 4 (unsupported object) and an error value of 2 (unsupported object type) in accordance with [ RFC5440 ].

Accordingly, some notable features of the present invention are as follows:

the SRv6 capability TLV was introduced in open messages exchanged during the PCEP session.

The indication information represented as bit (I) is defined in the SR-ERO and SR-RRO sub-objects.

Introduce PATH-SETUP-TYPE (2) to support IPv6 SR (SRv6) based tunnel establishment.

Although implementations of the method of establishing ipv6 segment routing (SRv6) tunnels by extending PCEP have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations of methods for establishing ipv6 segment routing (SRv6) tunnels through extended PCEPs.

The embodiment of the invention provides a PCE in a network. Fig. 10 is a schematic diagram of a PCE provided by an embodiment of the present invention. Other portions of the PCE may be referred to in the PCE art and the present invention will not be described.

As shown in fig. 10, the PCE includes a transceiving unit 1001 and a processing unit 1002. Wherein the transceiving unit 1001 is configured to perform a receiving action and a transmitting action performed by the PCE in the method 100, 200, or 300 shown in fig. 1-3, and the processing unit 1002 is configured to perform other actions than the receiving action and the transmitting action in the method 100, 200, or 300. For example, the processing unit 1002 is configured to generate a first path computation element communication protocol (PCEP) message, wherein the first PCEP message includes indication information and a Segment Identifier (SID) field; the SID field comprises a plurality of SIDs, and the indication information is used for indicating that each SID in the plurality of SIDs is respectively an IPv6prefix of a node in a tunnel; the transceiving unit 1001 is configured to send the first PCEP message to a first Path Computation Client (PCC) to establish an IPv6 segment routing (SRv6) tunnel from the first PCC to a second PCC according to the SID and the indication information. The detailed description refers to the above method embodiments, and is not repeated herein.

Corresponding to the methods illustrated in fig. 1-3, an embodiment of the present invention also provides a PCE 600. Referring to the schematic diagram shown in fig. 11, the PCE may include: a processor 501, a memory 502, a transceiver 503 and a bus system 504, wherein

The bus system 504 is used for connecting the processor 501, the memory 502 and the transceiver 503;

the transceiver 503 is used to perform the receiving action and the sending action performed by the PCE in the methods 100, 200, or 300 shown in fig. 1-3;

the memory 502 is used to store program instructions and data; and

the processor 501 is configured to read the program instructions and data stored in the memory 502 to perform the other actions of the method 100, 200 or 300 except the receiving action and the sending action. For example, the processor 501 is configured to generate a first path computation element communication protocol (PCEP) message, wherein the first PCEP message includes indication information and a Segment Identifier (SID) field; the SID field comprises a plurality of SIDs, and the indication information is used for indicating that each SID in the plurality of SIDs is respectively an IPv6prefix of a node in a tunnel; the transceiver 603 is configured to send the first PCEP message to a first Path Computation Client (PCC) to establish an IPv6 segment routing (SRv6) tunnel from the first PCC to a second PCC according to the SID and the indication information. The detailed description refers to the above method embodiments, and is not repeated herein.

As shown in fig. 12, the PCC includes a transceiver unit 3001 and a processing unit 3002. Wherein the transceiver unit 3001 is configured to perform a receiving action and a transmitting action performed by the PCC in the method 100, 200, or 300 shown in fig. 1-3, and the processing unit 3002 is configured to perform other actions in the method 100, 200, or 300 except the receiving action and the transmitting action. For example, the transceiving unit 3001 is configured to receive a first path computation element communication protocol (PCEP) message from a Path Computation Element (PCE), wherein the PCEP message includes an indication information and a Segment Identifier (SID) field, the SID field includes a plurality of SIDs and the indication information is used to indicate that each SID of the plurality of SIDs is an IPv6prefix of a node in a tunnel; and the processing unit 3002 is configured to establish an IPv6 segment routing (SRv6) tunnel from the first PCC to a second PCC according to the SID and the indication information. The detailed description refers to the above method embodiments, and is not repeated herein.

Corresponding to the methods shown in fig. 1-3, an embodiment of the invention also provides a PCC 600. Referring to the schematic shown in fig. 13, the PCC may include: a processor 601, a memory 602, a transceiver 603 and a bus system 604, wherein

The bus system 604 is used for connecting the processor 601, the memory 602 and the transceiver 603;

the transceiver 603 is configured to perform the receiving and transmitting actions performed by the PCE in the methods 100, 200, or 300 shown in fig. 1-3;

the memory 602 is used to store program instructions and data; and

the processor 601 is configured to read the program instructions and data stored in the memory 602 to perform the actions of the method 100, 200 or 300 other than the receiving action and the sending action. For example, the transceiver 603 is configured to receive a first path computation element communication protocol (PCEP) message from a Path Computation Element (PCE), wherein the PCEP message includes an indication information and a Segment Identifier (SID) field, the SID field includes a plurality of SIDs and the indication information is used to indicate that each SID of the plurality of SIDs is an IPv6prefix of a node in a tunnel; and the processor 601 is configured to establish an IPv6 segment routing (SRv6) tunnel from the first PCC to a second PCC according to the SID and the indication information. The detailed description refers to the above method embodiments, and is not repeated herein.

A processor in the present invention may be implemented by one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitry, and/or any devices that operate on signals based on operational instructions. Among other capabilities, at least one processor is configured to retrieve and execute computer-readable instructions stored in the memory to implement the methods of the present invention.

A system is provided, wherein the system comprises: a PCE according to any of the above PCEs and a PCC according to any of the above PCCs.

From the foregoing description of implementations, it will be apparent to those skilled in the art that some or all of the steps of the methods in the embodiments may be implemented by software, in addition to general hardware platforms. Based on this understanding, the technical solution of the present invention may be implemented in the form of a software product, essentially or as a contribution to the art. The software product may be stored in a storage medium such as a read-only memory (ROM), a RAM, a magnetic disk or an optical disk, and includes several instructions to instruct a computer device (which may be a personal computer, a server or a network device such as a media gateway) to execute the method described in the embodiments or some embodiments of the present invention.

It should be noted that the embodiments in the present specification are all described in a progressive manner, the same or similar parts between the embodiments may be referred to the embodiments, and each embodiment is described with emphasis on differences from other embodiments. In particular, network device and system embodiments are substantially similar to method embodiments and are therefore described briefly, with reference to the description of the method embodiments in relevant portions. The described network device embodiments are merely exemplary. Units described as separate components may or may not be physically separate, and components displayed as units may or may not be physical units, may be located in one location or may be distributed over a plurality of network elements. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the embodiment. One of ordinary skill in the art can understand and implement the embodiments of the present invention without inventive effort.

The foregoing description is only an alternative embodiment of the invention and is not intended to limit the scope of the invention. It will be apparent to those skilled in the art that certain modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.

Claims

1. A method of communication, performed by a Path Computation Element (PCE), the method comprising:

generating a first path computation element communication protocol (PCEP) message, wherein the first PCEP message includes a Segment Identifier (SID) field including a plurality of version six internet protocol forwarding plane segment routing segment identifiers (SRv6SIDs), wherein each SRv6SID corresponds to an IPv6 address;

sending the first PCEP message to a Path Computation Client (PCC).

2. The method of claim 1, wherein prior to generating the first PCEP message, the method further comprises:

receiving a second PCEP message sent by the PCC, where the second PCEP message includes a first SRv6 capability type length value TLV, and the first SRv6 capability TLV is used to indicate that the PCC supports SRv 6; and

sending a third PCEP message to the PCC, the third PCEP message including a second SRv6 capability TLV, the second SRv6 capability TLV to indicate that the PCE supports SRv 6.

3. The method according to claim 1 or 2, characterized in that the method further comprises:

sending a Path-SETUP-TYPE TLV to the PCC, the PATH-SETUP-TYPE TLV indicating that the PCC establishes a PATH based on SRv 6.

4. A method according to any of claims 1-3, wherein the first PCEP message is a path computation initiation request, pcinite, a path computation reply (PCRep), a path computation status report (PCRpt) or a path computation update request (PCUpd) message.

5. The method of any of claims 1-4, wherein the first PCEP message comprises SRv6 a display route object (SRv6_ ERO) sub-object, wherein the SRv6_ ERO sub-object comprises the SID field.

6. The method according to any one of claims 1-5, further comprising:

receiving a fourth PCEP message sent by the PCC, the fourth PCEP message comprising SRv6 route record object (SRv6_ RRO) sub-objects, wherein the SRv6_ RRO sub-objects comprise a plurality of SRv6SIDs, and each SRv6SID in the SRv6_ RRO sub-objects corresponds to an IPv6 address.

7. The method of claim 6, wherein the fourth PCEP message is a path computation state report (PCRpt) message used by the PCC to deliver a true path to the PCE.

8. A method of communication performed by a Path Computation Client (PCC), the method comprising:

receiving a first path computation element communication protocol (PCEP) message from a Path Computation Element (PCE), wherein the first PCEP message includes a Segment Identifier (SID) field including a plurality of version six internet protocol forwarding plane segment routing segment identifiers (SRv6SIDs), wherein each SRv6SID corresponds to an IPv6 address;

the PCC obtains the plurality SRv6SIDs from the first PCEP message.

9. The method of claim 8, wherein prior to receiving the first PCEP message, the method further comprises:

sending a second PCEP message to the PCE, the second PCEP message including a first SRv6 capability type length value, TLV, the first SRv6 capability TLV to indicate that the PCC support SRv 6; and

receiving a third PCEP message sent by the PCE, the third PCEP message including a second SRv6 capability TLV, the second SRv6 capability TLV indicating that the PCE supports SRv 6.

10. The method according to claim 8 or 9, characterized in that the method further comprises:

receiving a Path-SETUP-TYPE (PATH-SETUP-TYPE) TLV sent by the PCE, wherein the PATH-SETUP-TYPE TLV indicates that the PCC establishes a PATH based on SRv 6.

11. The method of any of claims 8-10, wherein the first PCEP message is a path computation initiation request (pcinite) message, a path computation reply (PCRep) message, a path computation status report (PCRpt) message, or a path computation update request (PCUpd) message.

12. The method of any of claims 8-11, wherein the first PCEP message includes SRv6 a display route object (SRv6_ ERO) sub-object, wherein the SRv6_ ERO sub-object includes the SID field.

13. The method according to any one of claims 8-12, further comprising:

sending a fourth PCEP message to the PCE, the fourth PCEP message comprising SRv6 route record object (SRv6_ RRO) sub-objects, wherein the SRv6_ RRO sub-objects comprise a plurality of SRv6SIDs, and each SRv6SID in the SRv6_ RRO sub-objects corresponds to an IPv6 address.

14. The method of claim 13, wherein the fourth PCEP message is a path computation status report (PCRpt) message used by the PCC to deliver a true path to the PCE.

15. A communication apparatus that functions as a Path Computation Element (PCE), comprising:

a processing unit to generate a first path computation element communication protocol (PCEP) message, wherein the first PCEP message includes a Segment Identifier (SID) field including a plurality of sixth version internet protocol forwarding plane segment routing segment identifiers (SRv6SIDs), wherein each SRv6SID corresponds to an IPv6 address;

a transceiving unit, configured to send the first PCEP message to a Path Computation Client (PCC).

16. The communications apparatus of claim 15, wherein the transceiver unit is further configured to:

receiving a second PCEP message sent by the PCC, where the second PCEP message includes a first SRv6 capability type length value TLV, and the first SRv6 capability TLV is used to indicate that the PCC supports SRv 6;

17. The communication device according to claim 15 or 16, wherein the transceiver unit is further configured to:

18. A communications device according to any of claims 15-17, wherein said first PCEP message is a path computation initiation request, pcinite, a path computation reply (PCRep), a path computation status report (PCRpt) or a path computation update request (PCUpd) message.

19. The communications apparatus of any of claims 15-18, wherein the first PCEP message comprises SRv6 a display route object (SRv6_ ERO) sub-object, the SRv6_ ERO sub-object comprising the SID field.

20. The communication device according to any of claims 15-19, wherein the transceiver unit is further configured to:

21. The communications apparatus of claim 20, wherein the fourth PCEP message is a path computation status report (PCRpt) message used by the PCC to deliver a true path to the PCE.

22. A communications apparatus that operates as a Path Computation Client (PCC), comprising:

a transceiving unit to receive a first path computation element communication protocol (PCEP) message from a Path Computation Element (PCE), wherein the first PCEP message includes a Segment Identifier (SID) field comprising a plurality of sixth version internet protocol forwarding plane segment routing segment identifiers (SRv6SIDs), wherein each SRv6SID corresponds to an IPv6 address;

a processing unit, configured to obtain the plurality of SRv6SIDs according to the first PCEP message.

23. The communications apparatus of claim 22, wherein the transceiver unit is further configured to:

sending a second PCEP message to the PCE, the second PCEP message including a first SRv6 capability type length value, TLV, the first SRv6 capability TLV to indicate that the PCC support SRv 6;

24. The communication device according to claim 22 or 23, wherein the transceiving unit is further configured to:

and receiving a Path-SETUP-TYPE TLV sent by the PCE, wherein the PATH-SETUP-TYPE TLV indicates that the PCC establishes a PATH based on SRv 6.

25. A communications device according to any of claims 22-24, wherein said first PCEP message is a path computation initiation request, pcinite, a path computation reply (PCRep), a path computation status report (PCRpt) or a path computation update request (PCUpd) message.

26. The communications device according to any of claims 22-25, wherein the first PCEP message comprises SRv6 a display route object (SRv6_ ERO) sub-object, the SRv6_ ERO sub-object comprising the SID field.

27. The communication device according to any of claims 22-26, wherein the transceiver unit is further configured to:

28. The communications apparatus of claim 27, wherein the fourth PCEP message is a path computation status report (PCRpt) message used by the PCC to deliver a true path to the PCE.

29. A communication apparatus that functions as a Path Computation Element (PCE), comprising:

a memory storing instructions;

a processor configured to execute the instructions to cause the communication device to perform the method of any of claims 1-7.

30. A communications apparatus that operates as a Path Computation Client (PCC), comprising:

a memory storing instructions;

a processor configured to execute the instructions to cause the communication device to perform the method of any of claims 8-14.

31. A communication system, comprising: a Path Computation Element (PCE) and a Path Computation Client (PCC), wherein the PCE is the communication device of any one of claims 15-21 and 29, and the PCC is the communication device of any one of claims 22-28 and 30.

32. A computer storage medium comprising instructions that, when executed in a processor, perform the method of any of claims 1-14.

33. A computer program product, characterized in that it comprises a program which, when run in a processor, implements the method of any one of claims 1-14.

34. A method of communication, performed by a Path Computation Element (PCE), the method comprising:

receiving a second path computation element communication protocol (PCEP) message sent by a PCC, wherein the PCEP message comprises a first SRv6 capability type length value TLV, and the first SRv6 capability TLV is used for indicating that the PCC supports SRv 6; and

35. The method of claim 34, further comprising:

36. The method of claim 34 or 35, further comprising:

37. The method of claim 36, wherein the fourth PCEP message is a path computation status report (PCRpt) message used by the PCC to deliver a true path to the PCE.

38. A method of communication performed by a Path Computation Client (PCC), the method comprising:

sending a second PCEP message to a Path Computation Element (PCE), the second PCEP message including a first SRv6 capability type length value, TLV, the first SRv6 capability TLV to indicate that the PCC supports SRv 6; and

39. The method of claim 38, further comprising:

40. The method of claim 38 or 39, further comprising:

41. The method of claim 40, wherein the fourth PCEP message is a Path computation State report (PCRpt) message used by the PCC to deliver a true path to the PCE.

42. A communication apparatus, functioning as a Path Computation Element (PCE), comprising a transceiving element configured to:

43. The communications apparatus as claimed in claim 42, wherein the transceiver unit is further configured to:

44. The communication device according to claim 42 or 43, wherein the transceiving unit is further configured to:

45. The communications apparatus of claim 44, wherein the fourth PCEP message is a Path computation State report (PCRpt) message used by the PCC to deliver a true path to the PCE.

46. A communication apparatus that functions as a Path Computation Element (PCE), comprising:

a memory storing instructions;

a processor configured to execute the instructions to cause the communication device to perform the method of any of claims 34-37.

47. A communications apparatus that operates as a Path Computation Client (PCC), comprising: a transceiving unit for:

48. The communications apparatus of claim 47, the method further comprising:

49. The communication device according to claim 47 or 48, wherein the transceiving unit is further configured to:

50. The communications apparatus of claim 49, wherein the fourth PCEP message is a Path computation State report (PCRpt) message used by the PCC to deliver a true path to the PCE.

51. A communications apparatus that operates as a Path Computation Client (PCC), comprising:

a memory storing instructions;

a processor configured to execute the instructions to cause the communication device to perform the method of any of claims 38-41.

52. A communication system, comprising: a Path Computation Element (PCE) and a Path Computation Client (PCC), wherein the PCE is the communication device of any one of claims 42-46 and the PCC is the communication device of any one of claims 47-51.

53. A computer storage medium comprising instructions that, when executed in a processor, perform the method of any of claims 33-40.

54. A computer program product, comprising a program for implementing the method of any one of claims 34-41 when the program is run on a processor.

55. A method of communication performed by a Path Computation Client (PCC), the method comprising:

generating a path computation element communication protocol (PCEP) message comprising a version six internet protocol forwarding plane segment routing record object (SRv6_ RRO) sub-object, wherein the SRv6_ RRO sub-object comprises a plurality of SRv6SIDs, each SRv6SID of the SRv6_ RRO sub-object corresponding to an IPv6 address;

sending the PCEP message to a Path Computation Element (PCE).

56. The method of claim 55, wherein the PCEP message is a Path computation State report (PCRpt) message used by the PCC to deliver a true path to the PCE.

57. The method of claim 55 or 56, further comprising:

receiving a Path-SETUP-TYPE (PATH-SETUP-TYPE) TYPE Length Value (TLV) sent by the PCE, wherein the PATH-SETUP-TYPE TLV indicates that the PCC establishes a PATH based on SRv 6.

58. A method of communication, performed by a Path Computation Element (PCE), the method comprising:

receiving a Path computation element communication protocol (PCEP) message sent by a Path Computation Client (PCC), wherein,

the PCEP message includes a version six internet protocol forwarding plane segment route record object (SRv6_ RRO) sub-object, wherein the SRv6_ RRO sub-object includes a plurality of SRv6 segment identification SIDs, and each SRv6SID of the SRv6_ RRO sub-object corresponds to an IPv6 address.

59. The method of claim 58, wherein the PCEP message is a path computation state report (PCRpt) message used by the PCC to deliver a true path to the PCE.

60. The method of claim 58 or 59, further comprising:

a Path-SETUP-TYPE (PATH-SETUP-TYPE) TYPE Length Value (TLV) sent to the PCC, the PATH-SETUP-TYPE TLV indicating that the PCC establishes a PATH based on SRv 6.

61. A communications apparatus that performs as a Path Computation Client (PCC), comprising:

a processing unit to generate a path computation element communication protocol (PCEP) message that includes a version six internet protocol forwarding plane segment routing record object (SRv6_ RRO) sub-object, wherein the SRv6_ RRO sub-object includes a plurality of SRv6SIDs, each SRv6SID of the SRv6_ RRO sub-object corresponding to an IPv6 address;

a transceiving unit for transmitting the PCEP message to a Path Computation Element (PCE).

62. The communications apparatus of claim 61, wherein the PCEP message is a path computation status report (PCRpt) message used by the PCC to deliver a true path to the PCE.

63. The communication device according to claim 61 or 62, wherein the transceiving unit is further configured to:

64. A communications apparatus that operates as a Path Computation Client (PCC), comprising:

a memory storing instructions;

a processor configured to execute the instructions to cause the communication device to perform the method of any of claims 55-57.

65. A communication apparatus that functions as a Path Computation Element (PCE), comprising:

a transceiving unit for receiving a path computation element communication protocol (PCEP) message sent by a Path Computation Client (PCC), wherein,

the PCEP message includes a version six internet protocol forwarding plane segment route record object (SRv6_ RRO) sub-object, wherein the SRv6_ RRO sub-object includes a plurality of SRv6SIDs, and each SRv6SID of the SRv6_ RRO sub-object corresponds to an IPv6 address.

66. The communications apparatus of claim 65, wherein the PCEP message is a Path computation State report (PCRpt) message used by the PCC to deliver a true path to the PCE.

67. The communications device according to claim 65 or 66, wherein the transceiving unit is further configured to:

68. A communication apparatus that functions as a Path Computation Element (PCE), comprising:

a memory storing instructions;

a processor configured to execute the instructions to cause the communication device to perform the method of any of claims 58-60.

69. A communication system, comprising: a Path Computation Client (PCC) and a Path Computation Element (PCE), wherein the PCC is the communication device of any one of claims 61-64 and the PCE is the communication device of any one of claims 65-68.

70. A computer storage medium comprising instructions that, when executed in a processor, perform the method of any of claims 55-60.

71. A computer program product, comprising a program which, when run in a processor, carries out the method of any one of claims 55-60.